CURRENT (A) LTC4040 2.5A Battery Backup Power Manager Fea T Descrip T n Step-Up Backup Supply and Step-Down Battery The LTC 4040 is a complete 3.5V to 5.5V supply rail bat- Charger tery backup system. It contains a high current step-up n 6.5A Switches for 2.5A Backup from 3.2V Battery DC/DC regulator to back up the supply from a single-cell n Input Current Limit Prioritizes Load Over Charge Li-Ion or LiFePO battery. When external power is avail- 4 Current able, the step-up regulator operates in reverse as a step- n Input Disconnect Switch Isolates Input During Backup down battery charger. n Automatic Seamless Switch-Over to Backup Mode The LTC4040s adjustable input current limit function n Input Power Loss Indicator reduces charge current to protect the main supply from n System Power Loss Indicator overload while an external disconnect switch isolates the n Pin Selectable Battery: Li-Ion (3.95V/4.0V/4.05V/4.1V) external supply during backup. When the input supply or LiFePO (3.45V/3.5V/3.55V/3.6V) 4 drops below the adjustable PFI threshold, the 2.5A boost n Optional OVP Circuitry Protects Device to >60V regulator delivers power from the battery to the system n Constant Frequency Operation output. n Low Profile (0.75mm) 24-Lead 4mm 5mm QFN Package An optional input overvoltage protection (OVP) circuit protects the LTC4040 from high voltage damage at the a T V pin. One logic input selects either the Li-Ion or the IN LiFePO battery option, and two other logic inputs pro- 4 n Fleet and Asset Tracking gram the battery charge voltage to one of four levels suit- n Automotive GPS Data Loggers able for backup applications. The LTC4040 is available in a n Automotive Telematics Systems low profile (0.75mm) 24-Lead 4mm 5mm QFN package. n Toll Collection Systems L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n Security Systems and PowerPath is a trademark of Analog Devices, Inc. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6522118, 6570372, 6700364, n USB Powered Devices 8139329. Typical a T Normal to Backup Mode Transition 4.5V Backup Application with 4.22V PFI Threshold Normal to Backup Mode Transition Waveform Waveform (LiFePO App.) 4 (Charge Current Setting: 1A, Input Current Limit Setting: 2A) 5 10 V SYS 1A 12m 4.5V SYSTEM 4.5V INPUT 4 8 LOAD SUPPLY V = 3.3V 2.2F BAT 1500k 100F I = 1A SYS 3 6 C = 100F SYS V CLN IGATE V V IN SYS IN 324k R = 2k 154k PROG OVSNS BSTFB 2 4 PFI RSTFB 2.2H 60.4k SW I BAT 1 2 FAULT 10F BAT LTC4040 V PFO IN RST 0 0 CHRG CLPROG NTC 2 1 CHGOFF BSTOFF F0 F1 F2 PROG 0.4 0 0.4 0.8 1.2 + LiFePO NTC 4 TIME (ms) 2k 3.6V 4040 TA01b V SYS 4040 TA01a 4040fb 1 For more information www.linear.com/LTC4040 VOLTAGE (V) ion pplica ions pplica ion uresLTC4040 a Te Maxi Mu M r a T p in c F T (Notes 1, 2) TOP VIEW V (Transient) t < 1ms, Duty Cycle < 1% .... 0.3V to 7V IN V (Steady State), BAT, CLN, V , IN SYS 24 23 22 21 20 BSTFB, NTC, OVSNS, 1 19 V PFI SYS CHRG, PFO, RST, FAULT ............................... 0.3V to 6V PROG 2 18 BSTFB F0, F1, F2, BSTOFF, RSTFB, CLPROG 3 17 NTC 25 CHGOFF 4 16 OVSNS PFI, CHGOFF ......0.3V to Max (V , V , V ) + 0.3V IN BAT SYS GND BSTOFF 5 15 IGATE I .................................................................. 10mA OVSNS 6 14 V F0 IN I , I , I , I ..........................................10mA CHRG PFO RST FAULT CLN 7 13 F1 I , I ....................................................... 1.1mA PROG CLPROG 8 9 10 11 12 Operating Junction Temperature Range (Note 3) ...................................................... 40 to 125C UFD PACKAGE Storage Temperature Range ...................... 65 to 125C 24-LEAD (4mm 5mm) PLASTIC QFN T = 125C, = 43C/W JMAX JA EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB